package com.codeforces.contest.c34;

import java.util.Scanner;

public class _34A {

	static Scanner scanner = new Scanner(System.in);
	static int n, mval, idx;
	static int[] sol;

	public static void main(String[] args) {
		n = scanner.nextInt();
		sol = new int[n+1];
		mval = Integer.MAX_VALUE;
		sol[1] = scanner.nextInt();
		for (int i=2;i<=n;++i) {
			sol[i] = scanner.nextInt();
			int val = Math.abs(sol[i-1] - sol[i]);
			if (val < mval) {
				mval = val;
				idx = i-1;
			}
		}
		int val = Math.abs(sol[n] - sol[1]);
		if (val < mval) {
			System.out.println(n + " " + 1);
		}
		else {
			System.out.println(idx + " " + (idx+1));
		}
	}

}
